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Thread: heads for 454

  1. #1
    KOZY
    looking to replace my standard performance oval port heads, would large oval be the way to go.

  2. #2
    BlackWidowBowTies
    I would highly recommend the "rectangle port" heads you speak of.
    I recently put the finishing touches on my latest 454, actually a .30 over. I prted and polished the heads to improve flow.
    With a few other goodies I achieved a naturally aspirated 630 hp. Not the greatest number in the world but its as solid a motor as I have ever seen. Forged bottom end and all. After porting and polishing I gained 27hp.

  3. #3
    hoolign
    just curious,ive just done 5000.00 {cdn} on a 1970 454 which was already bored .30 over with 11 1/2:1 trw pistons had the heads ported and polished {peanut heads},5000rpm cam,roller rockers,valves and guides,it runs 114 octane through a 850 holley dbl pumper and it dyno'd at 525 horse,what {goodies}did you add? yo get630

  4. #4
    spectras only
    Hi guys,I have a legitimate 454 LS6 in my 24 daycruiser.They come with forged crank,pistons,rectangular heads, solid lifters,11,1/4 compression, heat treated rockers and forged rods.The factory rated horsepower is 450.To gain 180 HP you need a lot more than polishing and porting.Polishing and porting only gives an advantage well over 6000RPM.If you contact Lingenfelter racing,they tell you not to bother with porting and polishing unless you are running in the 7000 RPM range.I turn 5000RPM with my stock LS6 on a 14/13 OJ 3 blade prop that gives me a theorethical 57/58MPH.To obtain 630HP I would need to change to a radical cam,a much higher comression ratio.I also run a 800CFM double pumper Holley.Lingenfelter is the undisputed Chevy guru when it comes for serious engine building.I would take his advise in future modification on my engine.By the way Cheetah boats built their boats in the 70's.You see some examples in reader rides.So go back some issues and yuo'll find some owners who would share their information.

  5. #5
    BlackWidowBowTies
    Originally posted by spectras only:
    Hi guys,I have a legitimate 454 LS6 in my 24 daycruiser.They come with forged crank,pistons,rectangular heads, solid lifters,11,1/4 compression, heat treated rockers and forged rods.The factory rated horsepower is 450.To gain 180 HP you need a lot more than polishing and porting.Polishing and porting only gives an advantage well over 6000RPM.If you contact Lingenfelter racing,they tell you not to bother with porting and polishing unless you are running in the 7000 RPM range.I turn 5000RPM with my stock LS6 on a 14/13 OJ 3 blade prop that gives me a theorethical 57/58MPH.To obtain 630HP I would need to change to a radical cam,a much higher comression ratio.I also run a 800CFM double pumper Holley.Lingenfelter is the undisputed Chevy guru when it comes for serious engine building.I would take his advise in future modification on my engine.By the way Cheetah boats built their boats in the 70's.You see some examples in reader rides.So go back some issues and yuo'll find some owners who would share their information.
    Engine was an origional LS6 as well, Contact Kim Barr Racing Engines in Dallas for actual Dynoed numbers 628hp to be exact. As the motor came from its origional manufacturer Guardian Marine it produced 572 hp with Bassett racing headers, which I am using.
    The origional LS6 was quoted by GM at 450. Actual numbers were 525 to 540 hp. Check out HP books BigBlock Chevy power,
    decent source for info. With all due respect, John Ligenfelter does build a mean motor, but Kim Barr has been a prostock racer and has been building race engines for 22 yrs. Hes on the all time fastest ProStock top 250.
    Anyway, I dont claim to know everything, by any means, but I do know I gained a realistic 29 hp from porting and polishing the heads, degreed the cam, and fine tuned the 850 dbl pumper Holley. Other than that I have a big Lunati cam, solid lift.
    I built the engine myself, very meticulous, gapless rings, 5 angle valve job, general goodies.
    I dont mean to offend anyone but I can produce dyno charts to attest to my engines hp rating of 630hp

  6. #6
    spectras only
    Hi bowties, can you give any cam specs,compression ratios and maybe some info on your boat's performance,ie; RPM-speed and drive specs?

  7. #7
    SPECTRABRENT
    I believe Cheetah boats is in Lake Havasu Az.
    SpectraBrent

  8. #8
    BlackWidowBowTies
    Spectras Only..
    My boat is a 1972 Cheetah. 19' 86"beam, full length stringers. Hull weight 900lbs. 18 degree deep v design.
    Pump is a Dominator MB12s with an "AA" SS impeller, 2 5-degree wedges. Place diverter. Pump has beem ballanced.
    Engine 454 bored .30 over. LS6 1972.
    Peened forged steel, cross drilled and chamferred, tufftrided crank.4 bolt mains.
    Completely balanced rotating assembly. Balancer to flywheel. Lunati solid lift cam model #SPB-2 550, 550. 110 degree centerline degreed to 108 degrees.
    Valve lash set to .22.
    Edelbrock TM2R Tarantula single plane manifold matched to heads, topped by a Holley Double pumper w/ mechanical secondaries at 850 cfm.
    Large rectangle port, ported and polished heads, 5 angle valve job, hardend seats. Competition spring job set for each valve.
    Gapless piston rings.
    11 1/2 to 1 compression forged aluminum pistons. Indexed spark plugs. Peened 7/16ths cap bolts.
    Vertex magneto and Bassett racing headers.
    Dyno tests done 3 months ago showed 628 hp at 6000 rpm.
    BWBT

  9. #9
    BlackWidowBowTies
    Not that it matters but I meant vlave lash set at .022 hehe sorry. some of you must have gotten a kick out of that hehehe.
    BWBT

  10. #10
    spectras only
    Hi Bow Ties,the camshaft specs sure indicate substantial increase over the stock LS6 camshaft and the racing headers help too,impressive figure anyway.What I'd like to know what RPM you running with the AA impeller with your present setup.Your compression ratio only went from factory 11:1 to 11.5:1.I have the HP book also and the maximum HP ever recorded in there is for the LS7 at 465HP.I'd like to know what did Guardian Marine to your engine prior to your rebuild to go to 572HP?!Let me know what speed you get out of your Cheetah with a GPS.Thanks

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